REFLECTOR: 1st flight N2084D

[Chuck Jensen]

Ah yes, we all shudder about rudder flutter.  Glad to hear you got back
uneventfully.  You must have had some good Velo-time recently if you were
comfortable at 80kts in the pattern, or was that just on approach?  And,
congratulations on adding the third dimension to your Velo!!
 
Related to this rudder issue, are the following true:
 
1) The rudder will tend to unload at higher speeds and start to flutter (as
apparently Dean's did)?
 
2) If flutter does start, will reducing speed and pressing hard on the
fluttering rudder (to reload it) likely stop the flutter?
 
Is there any number/measure of rudder incidence that is understood to be
getting close to unloading the rudder(s)?  Or, is it just trial and error to
determine how much we can unload them (to gain speed by reducing drag) until
we unload them too much?
 
Non-aero engineers want to know.
Chuck

-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of dean fitzbag
Sent: Sunday, August 01, 2004 10:50 AM
To: reflector
Subject: REFLECTOR: 1st flight N2084D


I made my first flight this morning.  It took me 21 months to build my
standard RG with no fast builds.
 
The flight started fine with only a little over zealous elevator at liftoff.
It handled well and before turning cross wind I retracted the gear.  The
airspeed was about 110 knots.  As I turned downwind I heard a few sounds
that sounded like an engine miss.  It quickly got very rough.  I thought the
engine was failing.  The aircraft was shaking badly.  I declared an
emergency and asked everyone to clear the area.  I reduced power right away
to improve chances of staying up longer and lowered the gear.  While looking
at the airport to plan which runway to set up for, I saw out of the corner
of my that my problem was left rudder flutter.  It was really shaking
everything.  Then as the airplane slowed to  100 knots the ride smoothed
out.  At 80 knots it was very smooth.  So I continued to fly a normal
approach and landing.  I'll call the factory tomorrow, but my guess is that
a shim will be recommended.
 
The factory was very helpful during building process.  Mike Pollack did my
EAA inspections and was provided very useful advice. 

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